Generally, a washing machine removes dust from laundry using chemical reaction of a detergent dissolved in washing water and friction between the washing water and the laundry due to rotating hydraulic power of the washing water generated by mechanical reaction, and selectively perform washing, rinsing, and dehydrating operations.
The above washing machine washes the laundry using one of various programs selected by a user.
Hereinafter, with reference to FIGS. 1 and 2, a washing operation of a conventional washing machine will be described in detail.
FIG. 1 is a block diagram of a general washing machine, and FIG. 2 is a flow chart illustrating a conventional method for controlling a washing operation of a washing machine.
As shown in FIGS. 1 and 2, a conventional washing machine comprises an input unit 11 for allowing a user to input a control signal for controlling operations of the washing machine, a controller 12 for controlling the overall operation of the washing machine according to an output signal of the input unit 11, a water supply valve driving unit 16 for operating water supply valves, such as a cold water valve, a hot water valve, and a shower valve, under the control of the controller 12, a drain valve driving unit 17 for operating a drain valve so that washing water supplied through the water supply valve driving unit 16 is drained, a water level sensing unit 14 for sensing a water level in a tub, a rotational speed sensing unit 15 for sensing a rotational speed of the tub, a motor driving unit 13 for operating a motor to perform a washing operation according to a control signal of the controller 12, and a heating unit (not shown) for heating or drying the washing water.
The operation of the above washing machine is controlled as described below.
As shown in FIG. 2, a washing program is selected according to kinds of laundry, such as cotton, synthetic fiber, and delicate material (S201).
Then, when a start key is inputted, a washing operation is performed according to a set washing course based on the selected program (S202). After the washing operation is completed (S203), dirty washing water resulting from the washing operation is drained to the outside of the washing machine (S204).
The laundry is intermittently dehydrated for a designated time. After the intermittent dehydrating of the laundry is completed, the laundry is dehydrated at a rotational speed differing from that of the intermittent dehydrating of the laundry for a designated time (S205).
After the dehydrating of the laundry is completed, a rinsing operation including supplying water, rinsing, and draining, is performed (S206).
Generally, the rinsing operations are repeated a designated number of times. After one rinsing operation is finished, it is determined whether or not the designated number of times of the rinsing operations have been performed (S207). When it is determined that the designated number of times of the rinsing operations have not been yet performed, another rinsing operation is performed (S208).
When it is determined that the designated number of times of the rinsing operations have been performed, the washing water is drained (S209), and the laundry is dehydrated (S210).
The above washing process is performed based on the set program. The washing process may be performed by other methods.
The above washing course and selection of the washing course of the conventional washing machine have several problems, as described below.
In the conventional washing machine, the selection of the washing course by a user is simply performed according to kinds of laundry without consideration of an individual using the laundry or a use of the laundry, thus being limited.
Currently, the increase of infant dermatitis, such as atopic dermatitis, due to the increase of environmental pollution has become an issue. The above selection of the simple washing course cannot effectively cope with this problem.
Particularly, clothes for infants need to be frequently washed due to growth characteristics of the infants. However, the above washing process does not consider the protection of the clothes for infants.
In order to increase a rinsing capacity of laundry during the rinsing operation, an additional rinsing operation selected by a user is performed. Here, the additional rinsing operation is limited in a rinsing effect, in which washing water not containing a detergent is supplied to the laundry to rinse detergent components and other contaminants out of the laundry.
The remaining of the detergent components and the other contaminants in the laundry easily affects weak skin of infants, thereby deteriorating user's reliability to the washing machine.